Project Summary In the current application, a collaborative, multidisciplinary research project is proposed to develop and validate an innovative platform to study the interactions between primary human intestinal cells and the pathogenic microbe, Clostridium difficile (C. difficile). A new and uniquely engineered technology will create an intestine-on-chip (organ-on-chip) platform capable of maintaining a viable human colonic epithelium co-cultured with luminal nonpathogenic and pathogenic obligate anaerobes in order to study fundamental cellular processes that occur during the interaction between the human and microbial cells. The work will design, model and engineer a three-dimensional intestinal-cell culture platform that supports a physiologic mucous layer as well as mimics the sheer forces of the passage of fecal material. The design of this system will make it possible to observe and perturb the human-microbe cell-cell interactions and modify respective environments to elucidate the underlying cellular and molecular events key to these interactions. A powerful attribute of the proposal is that these experiments will leverage new stem-cell culture methods that produce a normal, primary human colonic epithelium rather than use tumor cell lines as the source of the mammalian cells. The experimental data generated by the proposed microphysiological system will in the future provide key information concerning prevention and treatment option(s) for C. difficile as well as provide a new technique for the study of other infectious organisms involving the gastrointestinal tract.